ATK push for US space flight independence via Liberty

[joek]

Just yesterday you were suggesting they went for a composite design for expediency.

And based on Rominger's statement, expediency, as in "We're trying to minimize any changes" appears to have been a significant factor.

[RyanC]

Would it be possible to REDUCE thrust from the 1st stage during an abort by explosively severing the nozzle

Just build in thrust termination ports on the 5th segment. Open those explosively if you need to decelerate the booster fast.

But then you've added mass to the booster; and most importantly of all; made it theologically suspect, as it is no longer "shuttle heritage"; since it's no longer just using five off the shelf SRB segments, but something 'new'.

[RyanC]

Or, burning pieces of propellant hit the parachutes (much bigger targets)...

This is really simple to solve, since we have gone back to spam in a can, with a proper launch abort system and boost-protective cover.

Just load up into the LAS computer a whole clutch of "exploded SRB" parameters, so that the computer will go

"hey, I've just aborted from a possibly exploded SRB at x airspeed and y altitude; so keep the LAS/BPC attached for z seconds as we coast on a ballistic path to get out of the burning propellant cloud, then jettison the LAS/BPC and fire parachute deployment charges."

[Go4TLI]

Just yesterday you were suggesting they went for a composite design for expediency.

And based on Rominger's statement, expediency, as in "We're trying to minimize any changes" appears to have been a significant factor.

Right. So some reason pushed them toward a composite CM. I have been suggesting it was due to mass so they could incorporate the cargo module.

I continue to suggest it is not simply because they participated, along with others, in a NESC pathfinder project that was known to be conservative and to give civil servants composite experience

[RyanC]

It [catastrophic nozzle blockage] has happened with the related Titan 7-segmented SRB however, so is not unheard of.

If we're using CNB to ding Ares I/Liberty, we should in all fairness ding DIRECT/Ares V/SLS, because they all have twice the chance of a CNB, and all have the added 'fun' of an explosive tank in between the SRBs.

[sdsds]

Rominger stated that the abort system would have to "pull a capsule off of a first stage that's still burning and outrun it".

Yes, that does sound vaguely familiar, and it is a good description of the abort system's job! The first stage burns for something like 110 seconds. On the trajectory which Ares 1 would have flown (a reasonable proxy for Liberty's trajectory), most of that burn would be at Q values where a powerful escape motor would at least have a chance of saving the crew in just the way Rominger describes. He might have been implying they are confident of non-zero chances of survival at every point along the trajectory. That would be great, especially if they have a way to share the reasons for that confidence with e.g. NASA, the FAA, and the 45th SW.

His presentation also listed a better than 1/1,200 loss of crew number for the system.

Yes but this might rely on probabilistic sophistry. In particular they might be multiplying a zero chance of survival times a near-zero chance of the event occurring. Spaceflight is risky, but zero chance of survival at any point along the trajectory might be a show-stopper no matter how good the overall LOC number looked.

phenolic plastic suspending a carbon matrix has been tested to this temperature. Similar to the nozzle material used on the RS-68 engine.

This material is sort of like artificial rock? And about as dense? Sure, the five segment booster might have plenty of mass margin for this. But the escape system needs to "close" too. More massive protective encapsulation requires more propellant and thrust from the escape motor. It might be a wickedly vicious cycle!

(As a personal opinion, I would very much like to see Liberty fly. My only concern is that it might take scarce funding away from systems that are even more exciting!)

[sdsds]

tell me when to stop.

At 5 segments.

For what it's worth, ATK agrees with you about stopping at 5 segments. They have high correspondence between their mathematical models of what takes place inside a solid rocket motor and their field test results. In particular they tested a six segment motor (a sub-scale one) and tacitly admit that would be too long and skinny for reliably safe combustion.

Unless their amazingly accurate mathematical models are flawed (or unless there is a manufacturing defect that slips through undetected) they can essentially guarantee there won't be catastrophic nozzle blockage in the five segment motor.

[Downix]

phenolic plastic suspending a carbon matrix has been tested to this temperature. Similar to the nozzle material used on the RS-68 engine.

This material is sort of like artificial rock? And about as dense? Sure, the five segment booster might have plenty of mass margin for this. But the escape system needs to "close" too. More massive protective encapsulation requires more propellant and thrust from the escape motor. It might be a wickedly vicious cycle!

(As a personal opinion, I would very much like to see Liberty fly. My only concern is that it might take scarce funding away from systems that are even more exciting!)

It's not quite that bad, but it is denser than RCC, similar to stainless steel.

Remember, the MLAS was designed for Orion, a system heavier than Liberty here. The added weight for this kind of insulation would bring them pretty close to parity based on my math.

[Robert Thompson]

So...

Liberty offers more thrust than NASA asked for.

Due to the nature of solids, the LAS has to be radically engineered to combat the forces unleashed by these solids which already offer more thrust than NASA asked for.

For all this thrust offered that NASA didn't ask for, the MLAS that might come to full development does not appear that it will offer the same confidence that has become standard with ULA's already costly 'assured launch'.

For all this thrust offered that NASA didn't ask for, Liberty depends on a foreign supplier and transatlantic logistical train for a show-stopping component.

Looks like a case of overdelivering while underdelivering and selling dependency as Independence, and the buyer beware to extraordinary degree.

Who pays for the excess thrust offered that NASA didn't ask for?

Who pays for the continuing costs of the radical MLAS which does not at present sound as promising as man-rating other assets that are more fully domestically produced?

[Jason1701]

NASA does not "ask for" thrust. They asked for end-to-end crew space transportation system proposals, and ATK gave them one. The proposal reveals cost data to NASA, and NASA decides whether they want to pursue it. No need for leading questions.

[Prober]

It [catastrophic nozzle blockage] has happened with the related Titan 7-segmented SRB however, so is not unheard of.

thx Ryan for bringing some new info into the thread.

[Lobo]

I think Jim or someone said once that they can only evaluate where a competitor meets spec, and can’t give “extra credit” for exceeding spec.  So technically, I don’t know that NASA could give them any extra credit for that capacity, but that’s not to say they won’t informally, if they see future advantage and/or cost savings in that extra capacity.

For an acquisition contract (as in competed under Federal Acquisition Rules); CCiCap is not an acquisition and evaluation is squisher.

Just wondering if this might be one of those things in the back of NASA’s mind that gives a little unofficial extra consideration for it?

And for good or bad, raises the spectre of Orion-SLS-etc competing via Liberty.  Undoubtedly that's causing heartburn in some quarters.  In any case, NOT a subject for this thread.

But once the Liberty LV is flying, could not NASA buy a launch on it, the same as they are doing with ULA and D4H for Orion's first unmanned test flight.  It wouldn't have to officially have anything to do with the commercial crew contract, would it?

[Jim]

But once the Liberty LV is flying, could not NASA buy a launch on it, the same as they are doing with ULA and D4H for Orion's first unmanned test flight.  It wouldn't have to officially have anything to do with the commercial crew contract, would it?

If they onramp it to the NLS II contract

[spacejulien]

The real question for the liberty rocket is: Will Safran Snecma and Astrium be able to get the Vulcain 2 engine to air start reliable? [...]

[...]
To answer your question: yes, they will be able to get the Vulcain 2 engine to air-start reliably. Basically they already have. A direct result of the investigation and improvements made after the failure.

and

[...]
Let us also recall that there are actual "issues" to be solved along the way to becoming operational and then there are the Internet forum generated incorrect issues. A good example being the non-air-startable Vulcain 2 engine. Remember?... wooo that was the big snag when the Liberty was first announced. And it turned out that there was no real problem there at all.

In this case it's probably a "Internet forum generated incorrect achievement" in that the Vulcain 2 air-start was practically already achieved by the changes/testing campaign after the 517 (Dec/2002) launch failure.

From [1]:
"In conclusion, the most probable cause of the failure of Flight 157 was the simultaneous occurrence of two aggravating factors:
a) the degraded thermal condition of the nozzle due to fissures in the cooling tubes
b) non-exhaustive definition of the loads to which the Vulcain 2 engine is subjected during flight
The board also noted that it would be difficult to simulate these
additional loads during ground tests."

To cope with problem a) the coolant flow in the nozzle tubes was increased as well as a thermal barrier coating on its inside was applied, to cope with b) the nozzle was reinforced by an outer jacket [2].

In order to more correctly simulate nozzle loads during ascent at reduced ambient pressure a load simulation device was developed, allowing to reduce the ambient pressure on the outside of the nozzle down to 200 mbar [3], page 4.

Additionally, "it was investigated to what extend the random loads seen in flight could be reproduced on ground. On one nozzle, tests were performed while reducing the engine chamber pressure and then creating significant jet separation in the nozzle. This jet separation excites the nozzle eigen modes and reproduces similar excitation compared to the flight loads." [4], pages 5f. This was performed to create an overexpanded flow in the nozzle, but has nothing to do with ignition conditions below 1 bar ambient pressure.

So the "altitude" testing was limited to reduced pressure loads on the *outside* of the nozzle and the simulation of buffeting. No ignition at reduced ambient pressure levels inside the nozzle.

This is my state of knowledge and I've recently (again) talked this over with a colleague formerly employed at the DLR test site. Thus, I'd like to see some proof for a.m. claim.

[1] http://www.esa.int/esaCP/ESA7198708D_index_0.html
[2] http://www.volvoaero.com/SiteCollectionDocuments/VAC/new%20site/documents/Vulcain2redesign.pdf
[3] http://www.onera.fr/eucass/2005/Proceedings/5.13.02.pdf
[4] Ferrando, James, Girard, Terhardt, Blasi, Johnsson, Dangaard; 2005; "Vulcain 2 Nozzle Extension, Integrated European Team and Advanced Computational Models to the Service of Nozzle Design"; AIAA-2005-4535; no public link available.
 

[kkattula]

...
So the "altitude" testing was limited to reduced pressure loads on the *outside* of the nozzle and the simulation of buffeting. No ignition at reduced ambient pressure levels inside the nozzle.
...

Yes, those documents show the tests starting at 1000 mbar (approx. sea level) and maintining that for about 10 seconds before reducing to 200 mbar (approx. 40,000 ft) after about 20 seconds.

Nothing about ignition at significantly higher altitude. IIRC, staging is likely to take place at 10 mbar or less.

Unless there were other tests someone could point to?

[Lobo]

So, after reading all of this, I suppose the question is, what is ATK’s shot at securing one of the 2.5 commercial crew awards during the downselect we are expecting this summer?

I keep going back and forth on this myself.  I think SNC has a good shot because it is a spaceplane, and I think there’s many that would be involved in the selection process that would favor that.  Would probably garner more media attention when a mini shuttle is landing at the SLF than a capsule landing in the ocean or desert.

However, Boeing seems to have a good design, and making good progress, and has a lot of experience and clout behind them.  So I really don’t see CST-100 NOT getting selected unless some catastrophic design flaw comes to light.

SpaceX is a crowd favorite, and seems to have a mixed bag of support from liberals and conservatives alike (for different reasons).  They have hardware (albeit cargo only) flying now, and I have a hard time seeing them not selected either, barring some catastrophic flaw that surfaces.

But ATK seems to be making a strong push here.  They seem to be on to a pretty good design, if you set aside all of the hate thrown at it by the anti-ATK and anti-CxP crowds.  It has potential for some synergy with Block 1B SLS for at least the first several SLS flight, as well as synergy with Orion via LM.  Seems the most likely to be launching from KSC as well, and it seems NASA wants to have other outfits utilizing KSC.  (which I’d like to see too).  They have lots of experience in the field similar to Boeing.  So I’m having a harder time not seeing them selected either.

I’ve kind of written off Blue Origin, unless I see something that pops out of left field with them.

So, there’s 4 outfits I can’t see NOT being selected, but likely only 2.5 contracts.
At least one outfit gets left out when the music stops in this game of musical chairs.  I think that would be ATK for awhile, but now, they seem to have a valid design, as well as a lot of clout. 

So who gets left out when the music stops?  I get more confused the more I look at it.

[FinalFrontier]

I think the big problem here is this, and pardon my language here, but this utterly stupid POS decision to downselect to this "2.5" thing in the first place.


Whatever happened to competition and the government getting out of the way? And why was it the RIGHT side of the aisle that killed the idea of a large commercial program? And what about American launch capability being a "priority" of national security? Where did that debate go?

What ever happened to actually oh, I don't know, caring about giving the people their space program back?


The big problem is partisanship. We would have a larger program here with more vehicles and companies involved if not for the political nonsense. That's what it always seems to boil down to, even with this being a private sector thing, capitol hill still finds a way to ruin it for us (the american people) with their senseless bickering and regulation. 

That's the reason why there is so much hair pulling over ATK, because alot of people don't like the design, and now we are potentially facing losing, what would arguably be, a far leaner/safer design instead because there simply is not room enough for everyone in this program now.

I think I'll stop there before I go into a full fledged rant. I could talk for hours about the political problems but it would not be constructive.

[Chris Bergin]

Don't rant, FF. It'll only derail the thread.

So, after reading all of this, I suppose the question is, what is ATK’s shot at securing one of the 2.5 commercial crew awards during the downselect we are expecting this summer?

A decision this thread will have zero impact on!

Last call for any important and previously unanswered questions before I request an interview with ATK and Mr Rominger.

[Downix]

Don't rant, FF. It'll only derail the thread.

So, after reading all of this, I suppose the question is, what is ATK’s shot at securing one of the 2.5 commercial crew awards during the downselect we are expecting this summer?

A decision this thread will have zero impact on!

Last call for any important and previously unanswered questions before I request an interview with ATK and Mr Rominger.

I'd ask for something too technical to be of interest to the masses, and likely not be suitable for such an interview.

[FinalFrontier]

Don't rant, FF. It'll only derail the thread.

So, after reading all of this, I suppose the question is, what is ATK’s shot at securing one of the 2.5 commercial crew awards during the downselect we are expecting this summer?

A decision this thread will have zero impact on!

Last call for any important and previously unanswered questions before I request an interview with ATK and Mr Rominger.

My question would be regarding MLAS, whether they plan to make any modifications to it and if so what/how they plan on doing different abort modes/sims, on the technical side of things of course. So similar to what Downix is suggesting.